The 3rd Generation Partnership Project (referred to as 3GPP) Evolved Packet System (referred to as EPS) consists of the Evolved Universal Terrestrial Radio Access Network (referred to as E-UTRAN), the Mobility Management Entity (referred to as MME), the Serving gateway (S-GW), the Packet Data Network Gateway (referred to as P-GW or PDN GW), the Home Subscriber Server (referred to as HSS), the 3GPP authentication, authorization and accounting (referred to as AAA) server, the Policy and Charging rules Function (referred to as PCRF) entity and other support nodes. FIG. 1 is a schematic diagram of the EPS system architecture in the related art, as shown in FIG. 1, the mobility management entity is responsible for control plane related work such as managing the mobility, processing the non-access layer signaling and managing the user mobility management context; the S-GW is an access gateway equipment connecting with the E-UTRAN and forwarding data between the E-UTRAN and the P-GW, and is responsible for caching paging await data; the P-GW is a border gateway of the EPS and the packet data network (PDN) and is responsible for the PDN access and forwarding data between the EPS and the PDN, and other functions; the S-GW and the P-GW belong to the core network gateway; the PCRF entity is a policy and charging Rules Function entity, it connects with an operator Internet protocol (referred to as IP) service network through the receiver interface Rx to access the service information, in addition, it is connected with a gateway device in the network through the Gx/Gxa/Gxc interface and is responsible for initiating the establishment of the IP bearer, thus guaranteeing the Quality of Service (referred to as QoS) of the service data and controlling the charging.
The EPS supports to inter-connect with the non-3GPP system, wherein, the interconnection with the non-3GPP system is implemented through the S2a/b/c interface, the P-GW works as an anchor point between the 3GPP and non-3GPP systems. In the system architecture diagram of the EPS, the non-3GPP IP system is divided into trusty non-3GPP IP access and untrusty non-3GPP IP access. The trusty non-3GPP IP access can be directly connected to the P-GW through the S2a interface; the untrusty non-3GPP IP access needs to be connected to the P-GW through the Evolved Packet Data Gateway (referred to as ePDG), and the interface between the ePDG and the P-GW is the S2b, the S2c provides the user plane related control and mobility support between the user equipment (referred to as UE) and the P-GW, and the mobility management protocol supported by it is the Mobile IPv6 Support for Dual Stack Hosts and Routers (referred to as DSMIPv6).
In the EPS system, the Policy and Charging Enforcement Function (referred to as PCEF) entity exists in the P-GW, the Gx interface (see FIG. 1) between the PCRF and the P-GW is used to exchange information. When the interface between the P-GW and the S-GW is based on the PMIPv6, the S-GW also has the bearer binding and event report function (referred to as BBERF) entity to perform the QoS control on the service data, and the Gxc interface between the S-GW and the PCRF is used to exchange information (see FIG. 1). When accessing through the trusty non-3GPP access system, the BBERF also resides in the trusty non-3GPP access gateway. The Gxa interface (see FIG. 1) is used between the Trusty non-3GPP access gateway and the PCRF to exchange information. When the UE is roaming, the S9 interface works as the interface between the host PCRF and the visited PCRF, at the same time, the Application Function (referred to as AF) of the service is provided to the UE, the service information used to make the policy and Charging Control (referred to as PCC) is sent to the PCRF via the Rx interface. In the 3GPP, the access point name (referred to as APN) can be used to find the corresponding PDN. Usually, a connection from the UE to the PDN is known as an IP connectivity access network (referred to as the IP-CAN) session. In the process of establishing an IP-CAN session, the BBERF and the PCEF respectively establish Diameter sessions with the PCRF, the policy charging information and the information used to customize the policy, which are used to control the IP-CAN session, are transmitted through these Diameter sessions.
The corresponding broadband forum (referred to as BBF) proposes the broadband policy control function (referred to as BPCF) entity, as shown in FIG. 2, the main function of the BPCF entity is to make the appropriate policy; the Policy Enforcement Point (referred to as PEF) usually resides in the fixed network transmission equipment, for example the broadband remote access server (BRAS)/broadband network gateway (referred to as BNG), and it works according to the appropriate policy made by the BPCF entity; the AAA stores the user subscription information. The AF makes the policy for the BPCF entity and provides the appropriate service information. Currently, the BPCF entity architecture is still relatively crude, and the relevant details are still in further development.
the scenario of the Fixed Mobile Convergence (referred to as FMC) concerned by the operators is to do the research based on the interoperability of the 3GPP and the BBF. For the scenario of the user accessing the mobile core network through the BBF fixed network, it needs to guarantee the QoS on the entire routing path of the data (the data is transmitted through the fixed and mobile networks). At the current stage, the S9* interface is used (between the PCRF entity and the BPCF entity). In order to better operate the service, the mobile operator expands the wireless coverage, and from the point of view of cost saving, a segment of the WLAN access line from the fixed network operator is rent. The UE accesses through the fixed network WLAN, since the data transmission is through the fixed network, when the mobile operator considers the fixed network operator as an untrusty network, the UE establishes an IP-Sec (IP security) tunnel with the ePDG to ensure that the data transmitted between the UE and the ePDG is encrypted, while the fixed network transmission equipment cannot know the contents of the transmission.
In the process of the UE accessing a mobile network through the fixed network, there might be the situation that the UE accessing the fixed network can not be perceivable by the BBF fixed network, at this time, the BPCF entity is unable to obtain some information necessary for establishing the S9* session, therefore, thus the S9* session cannot be initiated to the PCRF.